Table 2.

Challenges to, and Potential Sources of Variability with, Expandable GDRFs

Challenges to Gastric Retention	Potential Sources of Variability
Mechanical: Digestive churn and housekeeping contraction waves	Behavioral factors: Eating habits, diet, fluid and alcohol consumption, physical activity.
Hydrodynamic: Propulsive and retropulsive jets of gastric fluid	Population diversity: pH, motility, and size differences; comorbidities; medications that alter gastric environment
Chemical: Enzymatic, acidic, and hydration-based digestive processes	Anatomical or physiological: mucosal abnormalities, surgical history, emesis